Handling and supporting device wafers during a wafer thinning process poses a challenge. A known approach for handling device wafers during the thinning process involves seven steps: 1) trimming; 2) coating; 3) bonding; 4) thinning; 5) treating; 6) affixing; and 7) debonding, as illustrated in FIGS. 1A through 1G, respectively. During the trimming step (FIG. 1A), a portion from a periphery of a first surface of a device wafer 101, having a plurality of solder bumps 103, is removed. The device wafer 101 is then coated with a bonding material 105, e.g. a glue material, and a carrier 107 is treated at 109 to allow bonding only around an outer edge, as shown in FIG. 1B. Next, the device wafer 101 is bonded to the carrier 107, as illustrated in FIG. 1C. Then, as illustrated in FIG. 1D, a second surface of the device wafer 101 is thinned. Once the desired thickness of the device wafer 101 is reached, a chemical edge treatment is performed on the bonding material 105, as illustrated at element 105′ in FIG. 1E. Next, the second surface of the device wafer 101 is affixed to a film frame or other substrate 111 and the device wafer 101 is separated from the carrier 107, as shown in FIG. 1F. Thereafter, the bonding material 105 and 105′ is removed from the device wafer 101 as illustrated in FIG. 1G. However the bonding material 105/105 may cause contamination of the wafer 101, and cleaning the bonding material 105/105′ from the front side of the device wafer 101, for example after the wafer 101 is on the film frame 111, is required.
Another known approach (not shown for illustrative convenience) involves creating separate zones, e.g., stiction/non-stiction, to prevent bonding of a full wafer, e.g., a 300 millimeter (mm) wafer, to a carrier wafer. However, this approach causes additional processing complexities and also requires cleaning of the front side of the thin wafer after the wafer is transferred to the film frame.
A need therefore exists for methodology for handling and supporting a device wafer during wafer thinning without a need for special treatment of the carrier and extra cleaning of the device wafer and without bonding material causing the front side of the wafer to become contaminated, and the resulting device.